/* 头部导航条 */
.tt-header{
  display: flex;
  position: fixed;
  box-sizing: border-box;
  width: 100%;
  max-width: 640px;
  height: 2.3rem;
  line-height: 2.3rem;
  text-align: center;
  top: 0;
  z-index: 200;
  border-bottom: 1px solid #ddd;
  background: #f8f8f8;
}

/* 左侧功能区 */
.tt-header > .left{
  flex: 0 0 3rem;
  /* flex-basis: 3rem; */
  text-align: center;
  /* flex-shrink: 0; */
}
/* 中间标题部分 */
.tt-header > .title{
  flex-grow: 1;
  overflow: hidden;
  white-space: nowrap;
  text-overflow: ellipsis;
}
/* 右侧功能区 */
.tt-header > .right{
  flex: 0 0 3rem;
  /* flex-basis: 3rem;
  flex-shrink: 0; */
}